Transmitter



Aug. 1, 1944.

E. T; BALDWIN TRANSMITTER Filed Feb. 26, 1945 2 Sheets-Sheet l INVENTOR.EDWARD T-. BALDWIN ORNEY.

Aug. 1, 1944. E. T. BALDWIN 2,354,733

. TRANSMITTER Filed Feb. 26, 1945 2 Shets-Sheet 2' FIG. 2

INVENTOR. EDWARD T. BALDWIN desirable number of sending units or areas.

Patented Aug. 1, 1944 TRANSMITTER Edward T. Baldwin,-River Forest, 111.,assignor to Chicago, 11]., a corpora- Tel'etype Corporation tion ofDelaware Application February 26, 1943, Serial No. 477,221 12 Claims.(01. 178-17) The present invention perta ns to printing tel'e-' graphtransmitters and more particularly to control means therefor.

The principal object of the present invention is to provide a controlcircuit for electricaliy operated devices wherein the value of currentis auto matically controlled under different operating conditions. i

Another object of the invention is to provide an improved arrangementfor operating tape controlled facsimile transmitters more efficientlyand economically.

A further object of the invention is to provide a means for controllingthe current supplied to the stepping magnet of a tape transmitter.

Specifically, the present invention concerns the more effective controlof a facsimile transmitterof the type disclosed in Patent No. 2390,0813to E. F. Kleinschmidt. Briefly, the transmitter therein disclosedcomprises a tape sensing device or record reader for sensingperforations in a tape perforated in accordance with a five-unit orBaudot code, which, through its electrical contacts, controls theenergization of a plurality of electromagnets, one individual to eachelement of the permutation code. These electromagnets serve to controlthe selective position of permutation bars, which accordingly will beset in varying combinations in accordance with the code combination ofperforations appearing in the perforated tape. The permutation bars foreach permuted setting serve to select a pair of brushes. Individual toeach pair of the brushes is a pair of code discs designed in accordancewith a method of prescanning in which the characters or symbols to betransmitted are divided into any The several units and areas thuscreated areassigned in the order of scanning to the periphery of a codedisc.

The code discs rotate continuously and the permutation bars are setpermutably in response to the energization of electromagnets, aspreviously outlined. Energization of the electromagnets is under thecontrol of atape sensing mechanism which receives its operating impulsefrom a cam operated contact which is operated in timed relation with therotation of the code discs. For each rotation of the discs and theindicated cam, an impulse is generated to effect the energization of anelectromagnet of the tape sensing mechanism to withdraw its tape sensingfingers and advance the tape to present the next transverse row ofperforations in alignment with the tape sensing elements of the sensingmechanism.

- ing screw; first,

sensing mechanism through the tape to present the next transverse row ofUnder predetermined conditions, it is desired to arrest the operation ofthe transmitter or the tape sensing mechanism, and therefore, anarrangement under the control of the condition of the perforated tape isprovided whereby the impulse generated cyclically through the operationof the transmitter pulsing cam will not be effective to energize the'electro'magnet of the tape sensing mechanism to'withdraw the sensingfingers from cooperation with the tape and advance the tape.

In accordance with established practice, the tape is prepared by eithera keyboard perforator or a signal controlled perforator and regardlessof the manner in which the tape is prepared a section of tape intervenesbetween the periorator and the tape sensing mechanism. Dependent uponthe condition of this intervening section of tape the impulse generatedby the cam, which may be identified as the pulsing cam, is effective orineffective.

Depending upon whether the tape between the perforator and the sensingmechanism is slack or taut, an electromagnet will be controlled fordetermining the position of an arm which is adapt ed to engage thethreadsof a continuously rotatto engage and close contacts forestablishing a condition to control the starting of the operating motorof the receivin printer at the receiving station, and second, to closecontacts to render the impulse generated by the pulsmg cam effective topermit operation of the tape the advancement of perforations inalignment withthe sensing fingers and permit transmission of impulses inaccord-- ance with such transverse row of perforations. Such a conditionprevails as long as the tape intermediate the perforator and the sensingmechanism does not become taut.

The present invention contemplates a new ar rangement of tapetransmitter pulsing me l;

anism. With the modifiedij pulsin echanism which controls thetapestepping mechanism of the tape transmitter, the tape stepping magnetis pulsed with one value of currentand maintained during idle time ofthe system by a lower .value of current. With the present invention, thecontrol Y during idle circuit for the tape transmitter is such thatcurrent is impressed on the tape stepping magnet time of the transmitteras well as during operating intervals, said circuit having tworesistances in series, and means comprising a screw and follower timingdevice and cam controlled instrumenta'lities for controlling, throughthe pulsing cam allows a contact in the circuit of the tape steppingmagnet to open and close cyclically. This circuit contains tworesistances to control plied to the tape sensing magnet. Duringoperation of the tape transmitter, at which time the tape steppingmagnet is pulsed cyclically by the rotation of the pulsing cam, it isdesired to slipthe amount of current sup-- the discs 13, the dark areasof a signal or message unit being the high surfaces M to engage a brushdesigned to cooperate therewith to send signal impulses. It is, ofcourse, obvious that the depressed or reduced portions of the code discsl3 represent the light areas of the signal or message unit. Obviously,the light areas might be made to be high surfaces, depending upon thepreferred method of transmission and of reproduction.

The term mechanical prescanning refers to the analysis of a character inthe signals suitable for transmission and comparable to the scanning ofthe character. The production of the mechanply a higher value of currentto the tape stepping magnet by shunting out one of said resistances.Mechanism according to the present invention is provided for controllingthe switching in and out of said resistance. Moreover, the arrangementacoperating coils during idle time of the transmitter.

According to another embodiment of the invention, the control magnet ofa distributor is protected against overheating by controlling the,

A more comprehensive understanding of the. present invention may be hadfrom the following description taken in conjunction with theaccompanying drawings, wherein like reference characters representsimilar parts throughout the several views, and in which; I

Fig. l is a schematic view of certain elements of the transmitteroperatively arranged with the tape sensing mechanism and control circuitfor governing the pulsing of the tape stepping magnet of the tapetransmitter mechanism;

Fig. 2 shows in perspective, elements of the transmitter adaptable forthe achievements A of the objects of the present invention; I 7

Figs. 3, 4, 5, and 6 areview's howing the various operating positions ofthe transmitter pulsing control mechanism; and V I e v Fig. 7 is aschematic view of another embodiment of the present'invention. A

Having reference to the drawings, particularly to Fig. 2, it is notedthat shaft 9 has secured thereto a pinion gear l0 which meshes with aworm gear ll driven by power communicated from a continuously rotatingmotor (not shown). The relation between gears I 0 and H is such as tocause rotation of shaft 9 at' a speed calculated to effect the accurateand proper distribution of current impulses indicative of the charactersto be transmitted. Secured also to shaft 9 are a plurality of code discsl1. 'These'code discs, as .best shown in the lower part of Fig. l, arecomposed of a plurality of discs arranged in pairs; that is, a pair ofcode discs l3 constitute 'a unit, one disc of which corresponds to alower case character, whereas the other disc corresponds to an uppercase character. V

Code discs [3 are designed accordinglto, a' method of prescanning inwhich characters or symbols to be transmitted are divided into anydeirable number of sending units or areas. The

several unit areas thus created are assignedin.

order of scanning to the periphery of eachof cording to this inventionincreases the 'tape stepping margins and reduces'the heating of the.ical member or disc containing elements thereb-y correspond directlyand individually to the signals and represents individual characters.For example, a character or letter may be prescanned by dividing itstotal area into a plurality of unit areas arranged in a predeterminednumber of vertical strips with a predetermined number of units withineach strip. The character is'thus divided into a plurality of stripslaid out in a predetermined number of equal angular sectors on the discsl3, and each angular sector is divided into a predetermined number ofangular units, each corresponding to a unit area of the correspondingvertical strips. The periphery of the code discs [3 is then laid out byrecessing the corresponding disc unit sections of each sector wherebythe respective unit areas are light; and where the units are dark,raised surfaces M are provided. With such a plan each of the code discs13 is correspondingly developed.

From the foregoing explanation of the arrangement of the code discs l3,it is evident that the present invention contemplates a code disc foreach character or symbol to be transmitted; that is, there will be acode disc l3 individual to each letter of the alphabet and each numeralor other special characters. These code discs, being secured to, butinsulated from shaft 9, will rotate therewith continuously, and duringtheir rotation, provided a selection has been established, will effectthe transmission of signal impulses indicative of their allocatedcharacter.

The discs I3 are arranged in pairs, and being so arranged, it isnecessary to interconnect a disc of each pair which, in turn, areconnected to a collector ring 15 which is also secured to shaft 9.Likewise, other code discs of each of the pairs of code discs areinterconnected and, in turn, are connected to a collector ring [6 which,as noted for collector ring I5, is also secured to shaft 9.Interconnection of the several code discs with the collector rings l5and i6, respectively, is achieved through the provision of conductorrods I1 and I8. These rods I1 and I8 are parallel to shaft 9 and extendthrough the code discs l3 and are connected to alternate code discs ofeach pair of code discs. Rods I1 and I8 are as shown in Fig. 1 connectedto collector rings l5 and I6, respectively.

In the operation of the transmitter constituting the present inventioncertainfunctional operations are required. Such functional operationsare performed by cams 24, 25,26, and 21 secured to shaft 9. These camsare positioned on shaft 9 with respect to each other and with respect tocode discs I3 to perform their respective functions in timed relationwith theother functional responses and the transmission ofsignal'ir'npulses as determined through'the rotation of code discs l3.It is obvious, therefore, that the cams 24, 25, 26, and 21 may beoriented on shaft- 9 with respect to each other to provide propersequential operation in a manner fully contemplated by the presentinvention. I

Positioned witl'rrespect to shaft 9 and the code discs l3 are aplurality of permutation bars 3|, 32, 33, 34, and 35, one individual *toeach element of the code. According to the embodiment of the inventiondisclosed, a'five-unit code is implied, and therefore there are fivepermutation bars, or one individual to each element or unit of the code.Operation of the permutation bars is attained through the arrangement ofan electromagnetindividual to each of the bars. Under such circumstancesthere are five electromagnets 37, 33, 39, 40, and 4|. Theseelectromagnets are selectively controlled from a tape sensing mechanism43 andcontrol, through their armature, a spring-held latch 44 whichengages a shoulder formed on the upper edge of its permutation bar tohold it against the action of its individual spring (not shown).

The tape sensing mechanism 43, as is fully and completely disclosed inPatent No. 1,460,357 to E. E. Kleinschmidt of June 26, 1923, embodies aplurality of tape sensing fingers 41 which serve to set perforations ina tape 48, which has been perforated through the operation of a keyboardperforator or a signal controlled reperforator to form transverse rowsof code perforations in dicative of the characters or symbols of themessage to betransmitted'through the effectiveness of code discs l3. Asis fully disclosed in the afore-mentioned patent No. 1,460,357, sensingfingers 41 are pivoted on a rod 49 and are movable about such rod by anelectromagnet 50. Specifically, electromagnet 50, upon being energized,draws itsma-gnetic yoke 5| to shift its core axially topusha nonmagneticpivoted bail plateli'z against the five tape sensing fingers 41 and thuswithdraw the sensing fingers 41 from engagement with the perforations intape 48 and causes,

following such withdrawal, the advancement of the tape through a ratchetand pawl mechanism (not shown) to present the next transverse row ofperforations inalignment. with the vertically projecting pins of thesensing fingers 47., The magnet core of the electromagnet 50 is, ofcourse, so designed as to respond in well-known manner to theenergization of said magnet, and said core is providedwith nonmagneticextensionswhich engage the bail 52.

Attached to and operated'by each of the sensing fingers. is a contactspring 54. There being five sensing fingers 41, there are five contactspringsv 54 which cooperate with stationary contacts 55 tonefiect acircuit closure and cause,

through the instrumentality of a battery, the energization of theelectromagnets connected thereto; that is, electromagnets 31 to 4|,

Assume, for example, that a sensing finger 4T encounters a perforationin tape 43. Through its contact spring 54 an energizing circuit for theelectromagnets 31 to 4| connected thereto will be established. Theelectromagnet will be energized and latch 44 will be operated againsttheaction of its spring to free the permutation bar individual thereto foraction by its spring. (not shown). Such permutation. bar will be moved.to theleft as viewed in Fig. 1. 7

Under certain conditions of operation, it is desirable to prevent theoperation of the tape sensing fingers 41, notwithstanding the fact thatthe electromagnet 50 may be energized cyclically.

In order to achieve such a result, a control circuit for the transmitterpulsing mechanism is provided whereby, notwithstanding the. fact that ismounted on shaft 9. cam 24, bail I6 will'have its knife-shapedporshunte'd'outautomatically thereby increasing: the

current supply to the magnet 55 duringrzeach cyclic rotation of thepulsing. cam '21; '5 This-are rangement will --be described morefullyherein+ after;

As shown in Figsg- 1 and 2, the lower 'edgefiof each ofthepermutationbarsfl .to 35 is-formed Avith a plurality of notchesarranged permutably so that-upon the perm'ute'dioperationofelectromagnets3'! to 4 l corresponding operation of permutation bars3| to.35'will result .inanialignment of-n'otches to effect the selectionof one 015a plurality of selectable bars 6| There is a select able bar6| individual to each pair of code discs l3. Each selectable bar BI isindividual to a: brush carrier or support 63 (Fig. '2) carrying a pairof brushes 65 and 66 for each pair of code discs-l3.

Each of the brush supports 63 has formed on oneof its arms a horizontalprojection 61 which lies in the path of its individual selectable bar 6sothat upon the operation of its bar 6|,brush support 63 will be'rotatedin a clockwise direction about rod 64, asviewed in Fig.2, against theactionof itsretractile spring:68,:.provided, however, the brush support63 is at that instant free to move. As shown in Fig. '2-,'the" brushsup;- port 63 has a horizontal extension 69 arranged with its end formedin a knife-like fashion-to cooperate: with a corre'spondinglyshap'edportion of a bail'lfl which extends transversely of the code discs [3and which is pivotally supportedat its ends by brackets H and 12. Formednear the left-hand end of bail I0 is a projection 13 to which isattached a. retractile spring 14 and a pivoted lever 16 which carries atits free end a .cam roller. 1'! positioned to be operated cyclicallyby'cam 24 which as previously described, Foreach operation of tion movedfree of the correspondingly'shaped projection 69 of the brush carrier631:0 release thebrush carrier 63, whereupon it is restored to itsnormal position orthe position shown in Fig. 2, by the action of itsindividual retractile spring 68.

Common to all selectable members 6| is a bail flit-which is pivotallymounted on rod 64 and which has vertically projecting arms. 45 "and.46

to which cam rollers operatively positioned with respect to cams 25and-26,. respectively, are secured. Retractile-springs 59 and 60 aresecured to arms .45. and 46, respectively. .For each rota,- tion of cams25 and 26; bail will be rotated counterclockwise, as viewed in Fig. 2,against the tension of springs 59'and 60 to move the selectable bars 6ifree of the permutation bars 3| to 35 to permit their operation, and.subsequently-will release the selectable bars 61 to permit one of suchbars to be selected through the alignment of a set ofv notches inpermutation bars 3| .to 35.

Whenthe permutation bars 3| to35 arepositioned in various combinations.in response to the permuted energization of electromagnets 31 -free-ofextension69 of its brushcarrier 63.. -.The

brushsupport.63.individua1 tothe operated sele'ctablebar 6I will bemoved againsttheaction of'its spring 68 to bring. the brushes 65 and66into operative relation with. respect to the pairjof code discs I3 towhich the operatedv brushsupport 63 is individual. Following the settingof the brush support 63, looking bail 10 is restored by its spring .14to a position where it engages extension 69 of brush support 63 andholds such brush support in its set position. The selectable member BIis thereupon free to be restored to its normal position out ofcooperation with the permutation bar 3| to 35 through the action of bail80,. and thus thepermutation bar may be reset to select either the sameselectable bar or another selectable bar v 6I identified withanotherpair of code discs I3. With .suchan arrangementrit is possibletofinitiate a selection during the interval the brushes 65 and 66 are inengagement with the code discs I3 for the transmission of signalimpulses characteristic of their peripheral formation. a

Following the selection of a selectable bar GI and the operation ofthebrush support 63, a cam (not. shown) mounted on shaft 9 is effective tooperate through a system of levers as fully disclosed in Patent No.2,176,740 to E. E. Kleinschmidt of October 17,1939, to restore each ofthe released permutation bars 3| to 35 to their normal position, or theposition shown in Fig. 1, wherein thebars are held against the action oftheir individual springs byv latches 44.

As previously described, a code disc I3 of each pair of code discsisuconnected to collector rings I and I6, respectively. Continuously inengagement with each of these rings are brushes 82 and83, respectively(Fig. 1). These brushes are connected-through electrical conductors tocontacts 84 and 85. Cooperating with these contacts is a contactor 86pivoted at one end and engaged at its other end with a rockable member81. Secured to member 81 are two oppositely arranged bell crank levers88 and 89 arranged to move member 81 to the left or right, dependingupon whether bell crank lever 88 or bell crank lever 89 is operated, tocause corresponding movement. of contactor 86 to engage either contact84 or contact 85.

Operation of hell crank levers 88 and 89 is achieved through selectorbars 90 and 9| individual thereto. Upon the selection and operation .ofeither of the selectable bars 90 and 9Iithe bell crank lever 88 or 89individual thereto will be operated and corresponding movements ofmember 81 will .be effected in well-known manner. Specifically, theselectable bars '90 and. 9|

identified withithe figures" and letters or shift-and unshift signalcombinations, respectively, and in accordance with the selection ofthebars 90 and 9I, the bar'81 will be shifted '.to switch the. arm. 86into contact with contacts:

84 or 85 which will thereupon connect the collector ring I5 or It to thesignal line, it being understood'that certain of the bars I3 areconnected to the collector ring I5 and other of the bars of'discs l3 areconnected to the collector ring I6, hence theefiective circuit'wi-lldepend upon-the positionofcontac'tor 86, which; as shown in Fig. 1, isconnected to a radiolfrequency transmitter 18 which may be of anywell-known design.

Positioned near the entrance end of the tape sensing mechanism 43 is amechanism commonly referred was a taut tape switchingrm'echeinis'mwhich'responds to the condition of 'the tape -to exercise controlfunctions. Such a'mechaits free end engages an insulated block securedto the free end of an electrical contact 96 which cooperates with anelectrical'contact 91 to control an electrical circuit which extendsfrom battery through a manually operated switch 99, contacts 9691 andthe windings of an electromagnet I03 to ground. Of course, with theswitch 99 open, the circuit for electromagnet I03 will not be completed;also, with contacts 96 and 91 open and with switch 99 closed, thecircuit of electromagnet, I03 will not be completed. However, with thelever 93 in the position shown in Fig. 1, which is its position when thetape 48 is looped as shown, contacts 96 and 91 will be closed, and withswitch 99 closed electromagnet I03 will be energized.v Q

As disclosed in Fig. 2, electromagnet I03 has its armature I04 pivotallymounted in a bracket I05 and held in its released position by a springI06. Pivotally attached to armature I04 is a vertically extending leverI01 which is moved to the position shown in Fig. 2, by a spring I08which has one end secured to arm I01 and the other end secured to afixed spring post. Secured near the free end of arm I01 is a pin or.worm follower I09 which, when electromagnet I03 is energized, engagesthe threads of worm 30, which as disclosedin Fig. 2 is formed in theleft-hand end of shaft 9.

The upper end of arm I01, as disclosed in Fig. 2, is beveled and isarranged during its movement from right to left, as viewed in Fig. 2,when electromagnet I03 is energized and when follower I 09 will bein-engagementwith the'thread of worm 30, to operate successivelycontacts H2 and H3. The contacts 2 and H3, as more 'fully' disclosed incopending application Serial No. 371,358 filed December 23, l940,-by R.E. Zenner, function to generate signal conditions which will causeoperationof-the radio transmitter 18 to transmitto the radio receiver 19a signal effective to control the operating circuit of the driving motorof the receiving printer which is connected to the radio receivernetwork 19.

The electromagnet 50 is included in a circuit extending from battery,through the winding of the magnet 50, over conductor II6, throughresistanc'es H1 and H8, over conductor H9, and then through contact I2I(closed cyclically by cam 21) to ground. When the magnet I03 isenergized upon the closing of switch 99 and tape switch contacts 96-91,as previously described, its armature I04 is attracted to bring the pinI09 on arm I01 into engagement with the threads of the worm 30, andsince the. worm 30 is constantly rotating, the arm I01 will be advancedtoward tromagnet I23 to ground.

When the magnet I23 thus becomes energized, itiwill pull up-its armatureI24 against the action of a spring I25. Armature I24 and. a lever cuitfor magnet 50 extending from positive bat- I I2Ii control the opening orn on-opening of the pulsing contact I2I upon the rotation of cam 21.Lever I26 is mounted on pivot I2I, as is also a control lever I28.Armature I24. is provided with an extension I29 carrying at itsupper'end a screw I3I which functions, upon the attraction of armatureI24 by magnet I23, to close a contact I 32 included in a shunt circuitaround the resistance II8. Lever I28 is normally biased in acounterclockwise direction by a spring I33, and is provided with a lowerhorizontal arm, the free end of which cooperates with the left-handspring of contact I32 in such a manner that when contact I32 is open,its left-hand spring acts to block or prevent the counterclockwiserotation of lever I28 by spring I33. Then, when the armature I24 pullsup, it causes the screw I3| to close contact I32 which frees theleft-hand spring of contact I 32 from engagement with arm I34 to permitcounterclockwise rotation of lever I28 by spring I33 to the positionshown in Fig. 6. In the position shown in Fig. 6, the lever I28 acts tolock the contact I32 closed against premature opening, which opening isgoverned, upon the deenergization of magnet I23, by the cam 21 actingupon the horizontal arm I35 of lever I28 so that the lever I28 isthereupon rotated clockwise to bring the arm I34 again under theleft-hand spring of contact I32.

The upper spring of contact I2I is provided with an insulating portionwhich cooperates with lever I26 which in turn is adapted not only tocooperate with cam 21 but also to have latching relation with armatureI24 of electromagnet I 23. With this arrangement, the armature of magnetI 23 under certain conditions of operation is latched behind (or to theleft of) the latching projection on lever I26 (as shown in Fig. 5) sothat the armature I24 cannot move toward the pole piece of magnet I23(upon energizae tion of said magnet) until cam 21 rotateslever I26counterclockwise to raise the latching end thereof free of armature I24,With this construction, it would be possible to withdraw the armature I24 of magnet I23 from under lever I26 at any point in the operatingcycle and'therefore open the circuit to the tape stepping magnet 50 atan improper instant in the operating cycle. With the armature of magnetI 23 obstructed by a projection on lever I 26, however, the armature I24cannot be removed from under the latching projection of lever I26 untilthis ob-. struction is removed by the proper positionment of cam 21 andthis action provides the proper timing in the operating cycle. Some lostmotion is provided between the lug I31 on lever I29 and contact IZI,whereby contact I2I-will not be opened unless armature I24 is removedfrom blocking relation with lever. I25 (as shown in Figs. 3 and 6)i/Vhen the lever I26 and the cam- 21 are in the relation with each otheras shown in Figs. 4 and 5, wherein these elements are shown in differentblocking relation with the armature I24, the contact I2I willremainclosed,

General operation In the operation of the. apparatus according to thepresent invention, the arrangement is shown in Fig. 1 in its idlecondition. Upon closing the manual switch 99 (assuming that the contacts969'I are closed due to the presence of a loop in the tape 48, andfurther assuming that the transmitting shaft 9 is continuously r tatingthus imparting rotation to cam 21) the contact I 2| will be operatedcyclically, the cirtery, through the winding of magnet 50, over theconductor II6, through the resistances Ill and H8, and through contactI2I (when closed) to ground. With the two resistances H8 and II! in thecircuit, the value of the current flowing therethrough is not ofsufficient strength to energize the magnet or solenoid 50. Thus, in thiscondition of operation, the contact I2I will be constantly opened andclosed, but the solenoid 50 will not beoperated. Moreover, in thiscondition of operation the solenoid 50 is independent of the manuallyoperated, switch 90. However, when theswitch 99 is' closed, and assumingthat the tape control contactsSB and 91 are also closed, a circuit willbe completed from battery, through the switch 99, through contacts96'9'I, over conductor I I 5 and through the magnet I03 to ground. Uponenergization of magnet I03 its armature I04 will be attracted to bringthe pin I09 on arm I01 into engagement with the threads of the worm 30thus causing the arm I0'I, to travel leftwardly until it closes thecontact H4, whereupon a circuit will be completed from positive battery,through the contact II 4, over conductor I22, and through the winding ofmagnet I23 to ground. Upon energization of magnet I23 its armature I24will be attracted, thus causing the screw I3I on the extension I29 toclose the contacts I32. However, this closure of contact I32 will notoccur until the cam 21 has reached its proper an, gular position withrelation to the lever I26, so that the notched right-:hand end. thereofis clear of the armature I 24, thus permitting the armature 124 to bepulled up completely by the magnet I23. When the armature I24,ha s beencompletely pulled up and the contact I 32 has been closed the arm I34 oflever I20 will be free to be rotated counterclockwise by the spring I33,thus locking the contact I32 closed for'at least the ensuing cycle ofrotationi'of carn .21. After" came 21 has i rotated 'a predeterminedamount it will cooperate with the arm I35 of lever I28 -to impartclockwise rotation to said lever I28 against the action of spring I33 toattempt to bring the arm I34 under the lefthand spring of contact I32,but if the magnet I23 is' still energized, the contact I32 Will stillbeheld closed, and the lever I28 will merelyoscillate back and forth underthe action of the cam 21. 7 Thus, the lever I26 will bear a relationwith the armature I 24, as shown in Fig.3, wherein the lever I26 is'rocked counterclockwise andv clockwise by the cam 21 under theinfluence, of spring I36. In this-connection it is noted that the leverI26 is providedwith a laterally pro- J'ecting lug; I3'I which cooperateswith the insulated portion of contact I2 I'so that, as the cam 21operates upon the lever I26" to urge it to' its extremecounterclockwiseposition against the action of spring I36, the contacts I2I will be permitted to" close due to their own spring tension, and the lug- I 31 willbe moved free of the insu lated portion. It is noticed that there issufficient lost'inotionbetwe'en' the lug I 31' and the insulated portionso that a certain degree of oscillation of lever I20 is permissiblewhile it is held'i'n the position'shown in Figs.'4 and 5.

As the contacts I32 have now become closed, the resistance H8 is shuntedout of theenergiz ing circuit forthe solenoid 50, thus permitting anincreased value of current to flow through the energizing circuittherefor, and accordingly upon each closureof contacts I2I by the cam2'I the circuit will extend from ground, through contacts I2I, overconductor II9, through con-' tacts I32, through resistance II1, overconductor H6, and through the winding of the solenoid 50 to battery.Therefore, upon each rotation of the cam 21 which constitutes a pulsingopera tion for the solenoid 50, said solenoid will be energized to causethe feeler arm 41 to sense the perforations in the tape 48, thus closingthe con-, tacts 54 and 55 according to the code combination sensed inthe tape and, in turn, causing the energization of corresponding magnets31 to 4I, and unlatching the corresponding latches 44 to permit the codebars 3| to 35 to be set ac-' cordingly to permit the selection of aselectable bar 6|.

This operation will be repeated successively until the taut tape switch96-91 has been opened by a taut or tight condition in the tape 48 (or bythe opening of the manual switch 99), whereupon the magnet I03 willbecome de-ener-. gized, and upon release of its armature I04 the arm I01will withdraw the pin I09 from the 205, through resistance 206, through204, through switch 201 4 its armature 203, and armature 203 has openedthe shunt contacts 209, current of lower value will thereafter beimpressed upon the winding of magnet 204, due to the introduction ofresistance 206 into its energizing circuit. This current of lower valueis of sufiicient strength to permit the worm thus permitting the springI08 to draw the arm I01 away from the contacts II4 opening the same andbreaking the energizing circuit for the magnet I23. Due to thisde-energization of magnet I23 the armature I24 will tend to re-- spondto the pull of its spring I25 to move away from the magnet I23. However,this movement of armature I24 is delayed by the lever I26 until the cam21 has rocked the lever I26 sufficiently counterclockwise to permit thearmature I24 to escape the latching end of the lever I26, thus causingthe opening of contact I32. Then. when the cam 21 operates upon the armI torotate the lever I28 clockwise, the arm I34 will be broughtunderneath the left-hand spring of contact I32 and thelever I28 will beheld in this, clockwise position against the action of spring I33 untilthe magnet I23will again become energized. The resistance I I6 willagain be introduced into the energizing circuit for the solenoid 'due tothe opening of the contacts I32, and hence insuflicient current will besupplied there-- after to the solenoid 50 to prevent operation of thesolenoid 50 and the tape sensing mechanism until a condition is createdwhereby the magnet I03 is again energized.

In Fig. '1 is illustrated a further embodiment of the present invention,wherein the magnet of a distributor is protected against overheating. InFig. '7, the distributor 20I is provided with a brush arm 202 whichcooperates with an armature 203 of the magnet 204. The energizingcircuit for magnet 204 extends from positive battery, over conductor205, through resistance 206, then through the coilsof magnet 204,through switch 201, to negative battery. A shunt circuit is providedaround resistance 206, including conductor 208, shunt contacts .209 andconductor 2I I. When the magnet 204 is de-energized, its armature 203 isbiased by spring 2I2 into the path of brush arm 202 to prevent rotationthereof.

Upon closure of switch 201. an energizing circuit for magnet 204 iscompleted from battery, over conductors 205 and 208, through contacts209, over conductor 2| I, through the winding of magnet 204, throughswitch 201, to negative battery As the magnet 20 4'becomes energized, itpulls up its armature 203, and in so doing, the armature 203 acts toopen the contacts 209 and thereby remove the shunt around the resistance206, after which the energizing circuit for magnet 204 will extend frompositive battery, over means well as during operating intervals, saidcircuit magnet 204 to hold its armature 203 attracted. Moreover, thisholding current is not of sufficient strength to overheat the coil ofmagnet 204. Thus, with the present invention, an arrangement is providedfor permitting sufiicient current to be supplied to magnet 204 to permitit to perform its predetermined operation, and thereafter to reduce thevalue of said current by automatically introducing in the circuit aresistance of suflicient size to maintain the magnet 204 energized aslong as it is desired to have the distributor 20I operate.

The invention has herein been described in a particular embodimentthereof. It is understood, of course, that the invention may be appliedto other forms of apparatus without departing from the spirit and scopeof the present invention, as defined by the appended claims.

' What is claimed is:

1. In a telegraph system, a transmitter having a record strip feedingmeans, a control circuit therefor wherein current is supplied to therecord strip feeding means during idle time of the transmitter as wellas during operating intervals, said circuit having two resistances inseries, and means comprising a screw and follower timing device and camcontrolled instrumentalities for controlling'through anelectromagnetically operated switching device, the shunting in and outof one of said resistances to vary the value of current supplied to saidrecord strip feeding means. 7

2. In a telegraph system, a transmitter having a record strip feedingmeans, a signal line, means for rendering said transmitter effective totransmit control impulses over said line including means responsive tothe condition of the record strip, a control circuit for said feedingmeans wherein current is impressed on said feeding during idle time ofthe transmitter as having two resistances in series, means controlled bysaid second mentioned means for rendering said record strip feedingmeans effective to transmit character signals over said signal line, andcam controlled instrumentalities for controlling, under the control ofsaid second mentioned means, the shunting in and out of one of saidresistances to vary the value of current supplied to said feeding means.

3. In a transmitter having strip feeding means, a control circuit forsaid means, pulsing means in said circuit, a plurality of currentcontrolling means in said circuit, shunting means for certain of saidcontrolling means, a supervisory circuit arrangement, and cam controlledinstrumentalities effective in cooperation with said supervisory circuitarrangement for controlling said shunting means for varying the value ofcurrent supplied to said strip feeding means.

4, In a transmitter having tape feeding means,

a control circuit for said means, pulsing means in said circuit, aplurality of current controlling means in said circuit, shunting meansfor certain of said controlling means, a first cam controlled means forgoverning the operation of said pulsing means, and a second camcontrolled instrumentality for controlling the operation of saidshunting means for varying the value of the current supplied to saidtape feeding means.

5. In a transmitter having tape feeding means, a control circuit forsaid means, pulsing means in said circuit, a plurality of currentcontrolling means in said circuit, shunting means for certain of saidcontrolling means, an electromagnetically controlled means, a first camoperated means for governing, under the control of said electromagnetically controlled means, said pulsing means, and a second camoperated instrumentality for operating said shunting means forvaryingthe value of current supplied to said tape feeding means,

6. In a transmitter having strip feeding means, a control circuit forsaid means, pulsing means in said circuit, current controlling means insaid circuit, shunting means for said controlling means, timing means,and cam controlled instrumentalities effective in cooperation with saidtiming means for controlling said shunting means for varying the valueof current supplied to said strip feeding means.

7. In combination, a first circuit including a magnet, an armature forsaid magnet, means for establishing said circuit, a second circuitcomprising pulsing means, current controlling means and an operatingmagnet, said operating magnet normally ineffective, shunting means forsaid current controlling means controlled by said armature, and camcontrolled means effective in response to the operation of said armatureupon the establishment of said first circuit for jointly maintainingsaid shunting means effective to shunt said circuit controlling means torender said operating magnet responsive to said pulsing means.

8. In a transmitter having tape feeding means, a control circuit forsaid means, pulsing contacts in said circuit, constantly rotating cammeans for successively operating said pulsing contacts, currentcontrolling means in said circuit, shunting means for said controllingmeans, timing means, and cam controlled instrumentalities effective incooperation with said timing means for controlling said shunting meansfor varying the value of current supplied to said strip feeding meansirrespective of the successive operation of said pulsing means.

9. In a transmitter having strip feeding means, a control circuit forsaid means, pulsing means in said circuit, a plurality of currentcontrolling means in said circuit, shunting means for certain of saidcontrolling means, timing means, and cam controlled instrumentalitieseffective in cooperation with said timing means for controlling saidshunting means for varying the value of current supplied to said stripfeeding means.

10. In a transmitter having tape feeding means, a control circuit forsaid means, pulsing contacts in said circuit, a current controllingmeans in said circuit, shunting means for said controllin means, asupervisory circuit arrangement, and cam controlled instrumentalitieseffective in cooperation with said supervisory circuit arrangement forcontrolling said shunting means for varying the value of currentsupplied to said strip feeding means.

11. In a transmitter having tape feeding means, a control circuit forsaid means, pulsing contacts in said circuit, constantly rotating cammeans for successively operating said pulsing contacts, currentcontrolling means in said circuit, shunting means for said controllingmeans, a supervisory circuit, and cam controlled instrumentalitieseffective in cooperation with said supervisory circuit for controllingsaid shunting means for varying the value .of current supplied'to saidstrip feeding means irrespectiveof the successive operation of saidpulsing means.

12. In a transmitter having tape feeding means, a control circuit forsaid means, pulsing contacts in said circuit, cam means for operatingsaid pulsing contacts, current controlling means in said circuit,shunting means for said controlling means, a supervisory circuitincluding an electromagnetic device for operating said shunting means,means controlled by said cam for governing the effectiveness of saidelectromagnetic device, and further means controlled by said cam andeffective under the control of said electromagnetic device forcontrolling said shunting means for varying the value of the currentsupplied to said strip feeding means.

EDWARD T. BALDWIN.

